don’t run travis for node 0.11

this is completely optional but makes sense consider 0.11 is the
non stable branch of node that only people who work on node itself
actively use, and b/c travis seems to fail about 80% of the time when
installing npm deps for v0.11

/cc @eastridge
Merge pull request #114 from walmartlabs/travis-remove-node-0.11

don’t run travis for node 0.11